Histological damage of saphenous venous wall treated in vivo with radial fiber and 1470 nm diode laser

Aim. Aim of this study was to evaluate the histological damage to the saphenous trunk after a 1470nm diode laser treatment performed by using a radial fiber. Methods. At the end of an endovenous laser procedure, five patients underwent a biopsy of a segment of the saphenous trunk, including a treated as well as a non-treated part of the vein. Such segments were all colored with Hematoxylin-eosin, and some of them also with Azan Mallory, Trichrome Masson, Van Gieson, Weigert, Alcian and Alcian-PAS. Results. Through microscopic analysis, the intimal layer was recognizable around all the vessel circumference, though with clear signs of coagulative necrosis also detectable in the tunica media, at a progressively deeper location correlated with the amount of delivered energy. Inside the tunica media, cavities and fissures were present. No histological signs of carbonization, vaporization or perforation were observed either on the intimal or media layers. All the described damage was widespread, uniform and constant around the whole vein wall circumference. Conclusion. Endovenous treatment of the saphenous trunks with a 1470 nm laser and radial fiber causes no contact damage. Vice versa, this procedure results in deep and uniform coagulation injury getting deeper as the delivered energy increases. The presence of cavities and separations in the tunica media suggests that a significant dose of energy is absorbed by the water of this layer and transformed into vapour, hence creating both thermal and mechanical damage.